Prepping for a Node.js interview? Here are 15 questions that come up again and again — with short, to-the-point answers. If you can explain these clearly, you're in good shape. Basics 1. What is Node.js? A runtime to run JavaScript outside the browser (built on V8). It's event-driven and non-blocking — great for I/O-heavy apps like APIs and real-time servers. 2. Is Node.js single-threaded? Your JS runs on one main thread, but Node offloads heavy I/O to libuv's background...